1#!/usr/bin/python
2
3# Copyright 2010 The Native Client Authors. All rights reserved.
4# Use of this source code is governed by a BSD-style license that can be
5# found in the LICENSE file.
6
7from __future__ import print_function
8
9import getopt
10import sys
11
12import elf
13
14USAGE = """Usage: elf_checker [options]* [filename]+
15
16This tools verifies alignment attributes of segments in elf binaries.
17If no attribute is specified via '-a' each segment in the binary is dumped.
18Otherwise, all options must be specified.
19
20Options:
21   -a (vaddr|paddr|memsz|filesz):  select the segement attribute to be checked
22   -s <name>:                      only consider segments with this name
23   -f <flag>:                      only consider segments with this flag value
24   -d <divisor>                    divide segment attribute by this number
25   -r <remainder>                  check division for this remainder
26"""
27
28
29def Fatal(mesg):
30  print(mesg, file=sys.stderr)
31  sys.exit(1)
32
33
34def DumpSegments(elf_obj):
35  for n, s in enumerate(elf_obj.PhdrList()):
36    print(n, str(s))
37
38
39def CheckSegments(elf_obj, attribute, segment, flags, divisor, remainder):
40  def ismatch(s):
41    return s.TypeName() == segment and s.flags == flags
42
43  filtered_segments = [p for p in elf_obj.PhdrList() if ismatch(p)]
44  if not filtered_segments:
45    Fatal('no matching segments found')
46
47  for s in filtered_segments:
48    print('found: ', str(s))
49    val = s.__dict__[attribute]
50    result = val % divisor
51    if result != remainder:
52      Fatal("%x %% %x == %x (expected %x)" % (val, divisor, result, remainder))
53
54
55def main(argv):
56  try:
57    opts, args = getopt.getopt(argv[1:], 'a:s:d:r:f:')
58  except getopt.error, e:
59    Fatal(str(e) + '\n' + USAGE)
60
61  flags = None
62  remainder = None
63  divisor = None
64  attribute = None
65  segment = None
66
67  for opt, val in opts:
68    if opt == '-r':
69      remainder = int(val, 0)
70    elif opt == '-s':
71      segment = val
72    elif opt == '-d':
73      divisor = int(val, 0)
74    elif opt == '-a':
75      attribute = val
76    elif opt == '-f':
77      flags = int(val, 0)
78    else:
79      assert False
80
81  if not args:
82    Fatal('no files specified')
83
84  if attribute is not None:
85    if attribute not in ['vaddr', 'paddr', 'memsz', 'filesz']:
86      Fatal('unknown attribute: %s' % attribute)
87    if segment is None:
88      Fatal('you must specify a segment name via -s')
89    if flags is None:
90      Fatal('you must specify segment flags via -f')
91    if divisor is None:
92      Fatal('you must specify a divisor via -d')
93    if remainder is None:
94      Fatal('you must specify a remainder via -r')
95
96  for filename in args:
97    data = open(filename).read()
98    elf_obj = elf.Elf(data)
99    if attribute is None:
100      DumpSegments(elf_obj)
101    else:
102      CheckSegments(elf_obj, attribute, segment, flags, divisor, remainder)
103
104  return 0
105
106
107if __name__ == '__main__':
108  sys.exit(main(sys.argv))
109